Single-acting engine.



B. BRAZELLE. SINGLE ACTING ENGINE.

APPLIOATION FILED MAY 31, 1912.

Patented June 24, 1913.

BENJAMIN BRAZELLE, OF ST. LOUIS, MISSOURI.

SINGLE-ACTING ENGINE.

Specification Letters Patent.

Patented June 24, 1913.

Application filed May 31, 1912. Serial No. 700,661.

b all whom it may concern:

Be it known that I, BENJAMIN BRAZELLE, a citizen of the United States, and a resident of the city of St. Louis and State of Missouri, have invented certain new and useful Improvements in Single-Acting Steam or Pneumatic Engines, of which the following is a specification.

The object of my invention is to provide a simple, compact and durable fluid pressure engine of the piston-hammer type adapted for application to drilling and chip ping rock, driving rivets, cutting metal, and analogous uses, to which end my improvements consist in certain novel constructions and combinations of parts as hereinafter described.

A further object of my invention is the elimination of small or frail Working parts and springs and the reduction of the number of working parts to a minimum.

The details of my invention. are more fully set forth in the appended claims.

- I have illustrated my invention in the accompanying drawings embodied in a portable stone cutting tool.

.In the drawings, in which like parts are designated by like characters wherever they occur, Figure 1 is a longitudinal section on the principal axis of the toolcylinder, showing the piston-hammer at the end ofits outward stroke; and Fig. 2 is asimilar view showing the piston-hammer near the end of its inward stroke.

Referring to the drawings, it will be seen that no springs and no very light and frail moving parts are contained in my improved device, and that the only moving parts, the piston-hammer, and the hollow cylindrical slidewalve, are large in size and substantial in form.

In my improved device the power cylinder is made in two parts, a barrel or casing l and a cylinder head 21, securely bolted together. The cylinder barrel is not uniform in diameter but for about half its length at the head end of the cylinder it is greater in diameter than at the other end of the cylinder. The enlarged ortion of the cylinder barrel contains the silide valve and the piston head of the difierential piston concentrically arranged therein; and the portion of less diameter serves as a casing and guide for the reduced outer or hammer portion of the piston which slides back and forth therein.

The outer end of the cylinder barrel or casing l is closed except for an axial cylindrical extension forming a tool socket 4 for the shank of 'a tool 5 which extends into the casing in position to be struck by the end of the piston-hammer. Upon the outside of the casing, at the end opposite the tool socket, is a handle. 3. An air inlet duct 12 controlled by a stop valve 13 is rovided on one side of the casing, to w ich inlet duct a supply pipe may be attached. This valve may be operated by alever or trigger instead of by the thumb-screw shown.

The slide valve 6 is a hollow cylinder, fitting snugly within the part of the power cylinder of larger diameter and having its end toward the handle 3, or head end of the engine, closed by a diaphragm 7 positioned a short distance from the end of the valve. This valve 6 is slidable axially back and forth within the casing and controls the admission of air or other motive fluid to and from the power chamber. The piston-hammer 8, with its differential piston portion 9 sliding within the valve 6 and its hammer portion 10 sliding within the smaller portion lot the casing, reciprocates back and forth Within the casing, at the outer end of its stroke hitting the shank of the tool successive blows. The side wall of the cylinder near the duct 12 is provided with an air inlet or supply port 14 in communication with the air duct when the stop valve is open. The cylinder wall is also provided with a longitudinal assage 11 at the ends of which are air cut 05 and air inlet ports 15, 16 communicating with the cylinder chamber near its mid portion and inner end, respectively. The cylinder head 21, which 0 oses the inner or head end of the cylinder, is formed with a central cylindrical projection 20 of less diameter than the cylinder, and forming with the cylinder wall an annular air space 19 for cushioning the end of" the valve 6. At the small end of the cylinder casin near the tool socket is a port 22 leading" irectly into the atmosphere. A small port 18 in the reduced portion ofthe cylinder casing communicates through connecting passages in the cylinder walls with a passage 17 in the inner end wall leading to is s i 11 and head end of the cylinder.

the head end of said power cylinder cl her. A port lroni the eyes er chamber near its head end directly llli f) the atmosphere.

ameter. This unit: "ion with the air inlet passage 2? in the o prevented from the screw :25, secured jecting into loi valve. 7 I I 30 adapted to register with. and uncover the air supply port is and the cut and inle: ports and 16, respectively, in the casing when the valve is at the head end of the cylinder, thus admitting air under pressure to the head end of cylinder if the stop valve open and the piston heck. Narrow slits 3'7; 3 :1 so out throu h the walls of the orlis 28 and 30, respectends i t s short dis ylinder,

tancc" toward and the slit i the cylinder. Q .i i l sir to pass slowly into the 1n front of or behind the p i vtert he latter in case it should become sirvlled at either end of its stroke. A port 31 in the slide-valve registers with the exhaust port 23 in the casing when the valve is at its extreme position away from the head end of the cylinder, thus opening :11 direct passage from the cylinder chamber to the 3tin0- sphere.

The operation of the device is as follows: In Fig. 2 valve 6 is shown at the extreme inner end of its stroke, and therefore all of the air inlet ports aireopen full and air is entering the casing and passing around the piston into the head end of the cylinder and nessing u on the entire areav of the piston ead 9. T e air pressure on the piston head drives the piston outward until its hammer mrtionstrikes the shank of the cutting tool 5. As the piston moves outward it will cover the air out 05 port 29 and out of? the further entrance of air into the passage The point in the stroke at which this cutting oil of the fluid pressure occurs may be varied hv changing the, location of the port :29, out.

prefer to locate it at about oneouarter of the full stroke of the piston. The air in the cylinder behind the piston will expand and a large part of the expansive force of this air willbe utilised in driving the piston forward, thus eoonomizing in the use of air. In case the piston is not stopped in its outrd travel i striking the shank of the 1 e s 52 and cylindrical ortion int thereto wil cone cesses line the air in the annular space surrounding; the latter and between the piston and inner end of the reduced portion of the cusing HIM, cushion the piston before it strikes fair enough outward for the inner edge 34E of the hammer poriion 10 to pass by and uncover the port l8 air will pass through the pori and communicating passages ning 17 into the space be of the slide valve and force iv from the head of the u the inlet ports into the cylinder chamber and opening 1" port 23, as shown in Fig, L e is alwn' s air under full pressure acting against the shoulder 32 tending to return the piston to the head end of the cylinder, when the pressure on the upper side of the piston is relieved by opening the -yl filer exhaust port the pres sure on the nor will overbalance the pressure in i pisi'on and it will be re head end thereby. Shortly ill reaches the end of its inouler end of the hammer ii snow-2r the port 18 and reon the head of the slide the valve to he returned-to r 'i by .the air pressure act-in upon the snnul 1 area' oi its opposite en The parts will then he in the positions shown in and ready for the admis" sion of air to the cylinder for another stroke. The sizes'of the passages and ports, and relative areas of the slide-valve and pieton faces, may be varied to obtain the desired speed of operation and force of blow. i-iltl'iough l have shown th portion 9 of '[liG piston provided with shallow grooves 35 for retaining oil and preventing eakage of the rear in-d stroke zj oii'tiou lii? v provide this portion with pecking'rings arranged in grooves similar to the elastic expanding pecking ring 3%; on the hammer portion 10 of the piston,

I do not desire to be restricted to the precise size, shape and arrangement of parts shown and described, but

What I claim and desire to secure by Letters Patent is as follows:

1. In a fluid-pressure enginefthe comhisir past the piston in either direction, I may,

casing l ghten the piston has traveled nation with a cylinder having an air supply ranged within said annular extension. a differential piston reciprocating within said valve and said smaller cylinder chamber, and means for admitting air alternately on each side of said closed end of said valve.

4. In a single acting engine having a differential cylinder comprising two axially arranged communicating chambers of difierent diameters, one end of the larger chamher being closed, said closed end containing an axial recess forming an extension of said lar er chamber, a hollow cylindrical valve slirfably arranged in said larger chamber with one end extending into said recess, a diaphragm in said valve, and means for admitting air alternately on each side of said diaphragm. I p

5. In a single-acting engine having a differential cylinder comprising two axially arranged communicating chambers of different diameters, one end of the larger chamber being closed, said closed end containing an axial recess forming an extension of said larger chamber, saidcylinder containing an annular groove surrounding the smaller chamber thereof and forming an extension of said larger chamber, a hollow cylindrical valve slidably arranged in said larger chamber with one end extending into said recess and its opposite end extending into said groove, a diaphragm in said valve, and means for admitting air alternately on each side of said diaphragm.

6. In a reciprocating engine, a cylinder having an air supply duct, a hollow cylindrical valve having an air inlet port adapted to communicate with said supply duct, an air cut-oil port, and an air outlet port, said valve reciprocating within said cylinder to open and close said inlet and outlet ports,

and a piston within said valve adapted to cover said valve cut-off port at a oredetermined point in its power stroke.

7. In a singleacting engine, a power cylinder terminating in a casing, a hollow cylindrical valve within said cylinder having an air inlet port, an air cut-ofi port, and an air outlet port, a diaphragm closing one end of said valve and means for alternately admitting air to each side of said diaphragm, said valve having its-open end toward the outer end of the casing, anda piston arranged for reciprocation within said valve, said piston having a reduced portion project ing from said valve and sliding Within said casing.

8. In a piston-hammer fluid pressure mo tor, a power cylinder, a sleeve valve niovably arranged within said power cylinder, and a difi'erential piston slidable within said valve,

said piston being provided withan annular groove for permittingpassage of air from the air supply to said valve during a portion of the power stroke.

9. In a piston-hammer fluid pressure motor, a power cylinder having an enlargement at its inner end and an outer endportion of less diameter, a sleeve valve movably arranged Within said enlargement, and a piston slidable within said valve, said piston being provided with a shank sliding in the portion of the cylinder of less diameter, and an expanding packing ring for preventing leakage of air between said shank and said power cylinder.

10. In a fluid-pressure engine, the combination with a cylinder having an air supply portand an air outlet port, of a cylindrical hollow valve controlling said ports, said valve containing an air cut 011' port, and a piston sliding Within said valve, the movement of said piston operating to close said out off port prior to the movement of said valve to open the outlet port.

Signed at St. Louis, Missouri, this 28th day of May, 1912.

BENJAMIN BRAZ'ELLE.

Witnesses A. M. HoLcor-mn, ALBERT H. CRoissANT. 

